This invention is in the field of environmental control devices and methods for live cell analysis.
High-content screening (HCS) is a cell-based screening method that yields temporal-spatial dynamics of cell constituents and processes. The information provided by HCS will alleviate bottlenecks in the drug discovery process by providing deep biological information. The assays associated with this method use either fixed or live cells. Fixed cells require no environmental conditioning because the biological information has been fixed in time. Live cells require the regulation of appropriate environmental conditions. The specific needs of a screen determine whether a live cell or fixed cell assay is advantageous. Fixing cells at a number of different time points can be time consuming. Therefore live cells assays save time when the kinetics of a cellular process need to be characterized. Furthermore live cell assays circumvent potential artifacts associated with a cell fixation process.
A number of environmental chambers have been described. For example, the Zeiss Environmental Chamber Incubator B (Carl Zeiss Inc., Thornwood, N.Y.) uses a moderately large (12.60xe2x80x3 long (L)xc3x978.66xe2x80x3 wide (W)xc3x973.54xe2x80x3 high (H)) acrylic incubator housing that surrounds the mechanical stage for an Axiovert microscope series. Two heating control systems exist; one is for the microscope stage and one is for the circulated air. The relatively large volume of the chamber requires that the air be preheated so that it does not cool the stage. The concentration of CO2 is controlled by mixing pure CO2 with warmed air and directly sensing CO2 concentration. The flow rate of the warmed air is also controlled.
The Olympus IX-IBM Incubator (Olympus America, Inc. Melville, N.Y.) uses a large (xcx9c24xe2x80x3 Lxc3x97xcx9c18xe2x80x3 Wxc3x97xcx9c18xe2x80x3 H) transparent acrylic incubator housing that surrounds the mechanical stage, condenser, and mechanical manipulators, of the Olympus IX70 microscope. The single heating system consists of a heater mounted to one of the side walls of the incubator housing and a temperature probe mounted within the housing. There is no air circulation and no source of CO2.
The Olympus IX-IBM CO2 Incubator (Olympus America, Inc. Melville, N.Y.) uses a small (xcx9c7xe2x80x3 Lxc3x97xcx9c7xe2x80x3 Wxc3x97xcx9c2xe2x80x3 H) transparent acrylic incubator housing that sits on the stage of an inverted microscope. Two heating systems exist: one for the circulated gas and one for the stage. Carbon dioxide is delivered to the chamber but its concentration is not controlled with a feedback system.
The Nikon Eclipse TE200 Incubator Accessory (Nikon, Inc. Melville, N.Y.) uses a large (xcx9c12xe2x80x3 Lxc3x9718xe2x80x3 Wxc3x97xcx9c18xe2x80x3 H) transparent acrylic housing that surrounds the mechanical stage and condenser of the Eclipse TE200 Microscope. The temperature of the interior gas can be set to within 3xc2x0 C. of the selected temperature. There is air circulation but no source of CO2.
U.S. Pat. No. 4,974,592 describes an environmental chamber that only controls temperature, and limits the user to a single sample per experiment. It does not accommodate commercially available multi-sample microplates, nor does it have a gas flow system. Instead the chamber volume is fluid filled to allow control of the chamber solution via a flow-through system. It delivers heat through electrically conductive material that is part of the sample holder. The temperature control technique has also been patented (U.S. Pat. No. 5,552,321).
Descriptions of environmental chambers for maintaining biological cells during imaging for basic research are common in the scientific literature (See, for example, Payne et al., J. Microscopy 147, 329-335 (1987); Boltz et al., Cytometry 17, 128-134 (1994); Moores et al., Proc. Natl. Acad. Sci USA 93, 443-446 (1996); and Bioptechs, Nature Biotech. 14, 361-362 (1996)). These laboratory devices tend to be specifically designed for a narrow range of applications including imaging and maintenance of a few tens of cells in one micro-chamber, or imaging and maintaining a specific cell type (e.g. amoebae, bacteria, or mammalian cells). Some provide thermal regulation and some allow flow-through of solution.
None of the existing environmental chambers combine (a) a plate space that can hold specimen plates of a variety of sizes, including but not limited to commercially available microplates, microscope slides, and biological microchips; (b) gas flow control; and (c) control of the temperature of the entire specimen plate.
Thus, there remains a need in the art for environmental chambers that combine (a) a plate space that can hold specimen plates of a variety of sizes, including but not limited to commercially available microplates, microscope slides, and biological microchips; (b) as flow control; and (c) control of the temperature of the entire specimen plate.
The present invention fulfills the need in the art for environmental chambers that combine (a) a plate space that can hold specimen plates of a variety of sizes, including but not limited to commercially available microplates, microscope slides, and biological microchips; (b) gas flow control; and (c) control of the temperature of the entire specimen plate. In a preferred embodiment, the present invention provides an environmental chamber for live cell screening comprising
a. a chamber housing comprising a plate space comprising a plate holder sized to permit insertion of a specimen plate, wherein the specimen plate comprises the bottom of the chamber housing when it is inserted into the chamber;
b. at least one gas inlet port;
c. a lid assembly comprising:
1. a lid with a top and bottom surface, wherein the bottom surface overlays the plate space in the chamber housing when the lid is closed; and
2. a heater attached to the top or the bottom of the lid.
In further preferred embodiments, the chamber further comprises one or more of a temperature control system, a gas flow control system, at least one gas inlet space, a chamber gasket, at least one gas outlet port, a lid cover, a lid insulator, and a lid latch. In a further preferred embodiment, the chamber housing, the lid and the lid cover are aluminum.
The present invention also provides methods for cell-based analysis comprising utilizing the environmental chamber of the invention for live cell analysis.